Spring type starter for internal combustion engines



Jan. 12, 1965 l. H. SVENDSEN 3,165,100

' SPRING TYPE STARTER FOR INTERNAL comsuswrow ENGINES Filed Jan. 22, 1964 4 Sheets-Sheet 1 omecnou 0F 5 (RANKING nzonmou Jan. 12, 1965 l. H. SVENDSEN 3,165,100

SPRING TYPE 'SJIARTER FOR INTERNAL COMBUSTION ENGINES Filed Jan. 22, 1964 4 Sheets-Sheet 2 Jan. 12 1965 l. H. SVENDSEN 3,165,100

SPRING TYPE STARTER FOR INTERNAL COMBUSTION ENGINES Filed Jan- 22, 1964 4 Sheets-Sheet s llllli Jan. 12, 1965 1. H. SVENDSEN 3,165,100

SPRING TYPE STARTER FOR INTERNAL COMBUSTION ENGINES Filed Jan. 22, 1964 4 Sheets-Sheet 4 United States Patent 3,165,1il0 SPRING TYPE STARTER FGR EXTERNAL COMBUSTIGN ENGHNES 11) H. Svendsen, Bjerriughro, Denmar assignor to Briggs & Stratton Corporation, Milwaukee, Wis., a corporation of Delaware Filed Jan. 22, 1964, Ser. No. 341,828 13 Ciaims. (Ci. 123-479) This invention, like that of the copending application Serial No. 223,351, filed September 13, 1962, of which this is a continuation-in-part, relates to starters for internal combustion engines and refers more particularly to engine starters of the spring windup type, wherein release of the energy of a wound up spring imparts engine-starting torque to the crankshaft of the engine through an overrunning clutch.

The Coughlin et al. Patent No. 2,999,489, illustrates an engine starter of the type with which this invention is concerned. In fact, the present invention might be said to stand upon the shoulders of that patent, since it constitutes an improvement upon the starter therein illustrated.

Although the starter of the Coughlin et al. patent is very reliable, and generally performs satisfactorily, it has one serious disadvantage which it shares with other prior starters of this type. With the Coughlin et al. starter, it is possible to bring the stationary part of the stop means by which the spring is held as it is wound up, into engagement with its coacting rotatable element while the engine is running. This is obviously objectionable, both from the standpoint of safety and the probability of breakage.

By contrast, this invention provides an engine starter especially adapted for use on small single cylinder engines such as those used to power lawn mowers, wherein the manually releasable stop means by which the spring is held as it is wound up and until its release is desired, cannot be engaged while the engine is running and, when once engaged, positively will remain engaged until it is intentionally manually disengaged.

Moreover, with this invention it is even impossible to deliberately engage the stop means whether the engine is running or not, since its engagement can be effected only automatically in consequence of relative motion between parts of the starter mechanism, which motion takes place as the operator beings to wind up the spring.

Another advantageous feature of this invention resides in the fact that before the spring can be wound up the overrunning clutch between the starter and the crankshaft of the engine will be engaged and will remain engaged until the engine starting operation has been completed. This makes the starter of this invention essentially shock free, since at no time during the starting operation is there a sudden application of a heavy load upon the starter mechanism, as is the case in starters in which the spring is wound up without first having the overrunning clutch engaged and the spring propelled driving element travels through an appreciable are before it picks up the load of the engine.

Still another attribute of this invention is that it permits several different locations of the handle by which the stop means is manually set. This flexibility facilitates adapting an engine equipped with the starter of this invention to different customer requirements.

Finally, this invention facilitates having the release mechanism located remotely from the engine, as for instance upon the handlebars of a lawn mower powered by an engine equipped with the starter of this invention, so that the operator need not be close to the engine when the starter spring is released.

With the above and other objects in view which will appear as the description proceeds, this invention resides 3,165,,idh

Patented Jan. 12, 1965 in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changesin the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.

The accompanying drawings illustrate one complete example of the physical embodiment of the invention constructed according to the best mode so far devised for the practical application of the principles thereof, and in which:

FIGURE 1 is a top view of a vertical shaft engine equipped with the starter of this invention;

FIGURE 2 is a cross sectional view through FIGURE 1 on the plane of the line 2-2;

FIGURE 3 is a horizontal sectional view through FIG- URE 2 on the plane of the line 3-3;

FIGURE 4 is a horizontal sectional view through FIG- URE 2 on the plane of the line 4-4;

FIGURE 5 is a detail sectional view through FIGURE 2 on the plane of the line 55, illustrating particularly the overrunning clutch through which the starter drives the engine crankshaft;

FIGURE 6 is an enlarged detail sectional view through the structure by which the spring is drivingly connected with the driving element of the overrunning clutch, to better illustrate the fact that this connection, though positive, has a limited degree of lost motion;

FIGURE 7 is a detail sectional view through FIGURE 4 on the plane of the line 77;

FIGURES 8 and 9 are detail sectional views taken through FIGURE 4 on the plane of the line 8 8, to illustrate the manner in which relative rotation between the inner end of the spring and the driving element of the overrunning clutch produces axial motion which is utilized to efi'ect automatic engagement of the stop means by which the spring is' held as it is wound up; and

FIGURE 10 is an exploded or separated perspective view of the starter.

Referring now particularly to the accompanying drawings in which like numerals indicate like parts throughout the several views, the numeral 5 indicates generally an internalcombustion engine of the single cylinder, vertical shaft type, now widely used on rotary power lawn mowers. The engine has the customary crankshaft 6, the upper end of which mounts a combined flywheel and air impeller, only the hub portion 7 of which is illustrated in FIG- URE 2.

As is well known, the combined flywheel and air impeller is located within a shroud or blower housing 8, by which the flow of cooling air induced by the impeller is directed over the hot parts of the engine.

Mounted on the shroud or blower housing 8 is the starter of this invention, indicated generally by the numeral 9. Being of the windup spring type, the starter 9 includes a spirally coiled torsion spring 16 and a handle 11 to wind up the spring. When released, the energy of the wound spring imparts engine-starting torque to the crankshaft 6 through a unidirectional overrunning clutch, indicated generally by the numeral 12. This clutch comprises a driven element 13 which is fixed to the upper end of the crankshaft, a driving element 14, and means to drivingly connect these elements for the transmission of torque in one direction.

Preferably the clutch 12 is of the type forming the subject matter of the Svendsen Patent No. 3,040,853, issued June 26, 1962. Accordingly, the driven element 13 of the clutch has a generally cup-shaped recess with a plurality of radially inwardly facing cam surfaces 15 against which balls 16 can be wedgingly engaged by a lobe 17 projecting from a hub portion 18 at the bottom of a the driving element 14. A cover 19 confines the balls in the recess of the driven member.

Engagement of the clutch takes place when the lobe 17 on its driving element wedges one of the balls 16 against the adjacent cam surface 15. To effect such engagement, some relative rotation between the driving and driven elements of the clutch in the engine-starting direction must take place; and it is one of the features of this invention that this necessary relative rotation and the engagement of the clutch is effected gently and without shock, and that the clutch remains engaged during the time the spring is wound up and thereafter until the energy of the wound spring is released and the actual cranking operation begins.

When the engine begins to turn over under its own power, the driven element of the clutch, of course, overruns the driving element and centrifugal force throws the balls 16 out into pockets 20 in the driven clutch element, where they will not come in contact with the lobe 17.

Most of the mechanism of the starter is contained within an inverted cup-shaped housing 21 which is conveniently formed as a stamping and has a substantially flat top wall 22 and a cylindrical side wall 23, the latter having legs 24 which project downwardly therefrom. at circumferentially spaced intervals, and are spot welded or otherwise solidly secured to the top wall 25 of the blower housing or shroud 8. A substantially flat wall 26 closes the bottom of the housing, being connected to the side wall 23 by tongues 27 on the latter struck inwardly over the edge of the wall 26 between radially outwardly projecting segments 28 which overlie the bottom edge of the wall 23.

The housing 21 is coaxial with the crankshaft and, as shown in FIGURE 2, the driving element 14 of the overrunning clutch projects upwardly into it through a hole 29 in the bottom wall 26.

Rotatably mounted in the housing 21 is an inverted cup-shaped spring cage 30 in which the spring 19 is located, with the end of its outer convolution hooked to the side wall 31 of the cage, as at 32. The top wall 33 of this inverted cup-shaped spring cage has its central portion formed into an upwardly projecting cylindrical boss 33, and this boss is journaled in a bearing 34 fixed in the top wall 22 of the housing 21.

The handle 11 is non-rotatably secured to the top of the boss 33' and, as in the aforesaid Coughlin et al. Patent No. 2,999,489, the handle has hingedly connected inner and outer sections which may be folded upon one another when not in use, and unfolded when it is desired to wind up the spring 10. A pawl 35 mounted on the underside of the inner section of the handle and coacting with ratchet teeth 36 on the exterior of the bearing 34, holds the handle against retrograde rotation as the spring is wound up.

In order to wind up the spring, it is of course necessary that its inner end be held against simply following along as the handle is turned, It is also necessary that the inner end of the spring be drivingly connected with the driving element 14 of the overrunning clutch, if the energy stored in the spring, when released, is to impart engine-starting torque to the crankshaft. Accordingly, the inner end of the spring is connected to a hub 37 which is situated within the housing of the starter and coaxial with the driving element 14 of the clutch. Axially the hub is held in place by having its ends bear against the bottom wall 26 of the starter housing and the top wall 33 of the spring cage.

For the reasons explained in the aforesaid Coughlin et al. Patent No. 2,999,489, the connection between the inner end of the spring and the hub 37 is formed by a link 38 pivotally connected to the hub and to the end of the spring. Although this manner of connecting the inner end of the spring with the hub permits the spring to overrun the hub as the starting operation is completed, and thus reduces the likelihood of breakage as described in the Coughlin et al. patent, it provides an unyielding spring-tensioning connection between the hub and the spring so that the hub 37, unless restrained, partakes directly of any motion of the inner end of the spring as the spring is wound up.

Six fingers or lugs 39 arranged in two diametrically opposite groups of three, project downwardly from the hub 37 through the hole 29 in the bottom wall 25 of the starter housing; and splined to these fingers or lugs is a ratchet disc 40 having teeth 41 on its periphery. Functionally, the ratchet disc 40 and the hub 37 could be one integral unit, but for assembly purposes the ratchet disc is a separate part splined to the hub in the manner described.

The teeth 41 on the ratchet disc are adapted to be engaged by a pawl 42 and, when thus engaged, the ratchet discand hence the hub 37-is secured against rotation.

The pawl 42 is mounted upon a stud 43 which is fixed to the bottom wall 26 of the starter housing, and which also has pivoted thereon a release lever or handle 44. A torsion spring 45 encircling the stud 43 and reacting between the pawl and the handle 44 at all times biases the pawl toward the toothed edge of the ratchet disc, but its engagement therewith is possible only when the handle 44 is in its Start position shown in full lines in FIGURE 4; and even then the pawl cannot be engaged with a ratchet tooth unless a lockout device, indicated generally by the numeral 46, has been moved out of its operative position.

To disengage the pawl 42 from the toothed edge of the ratchet discassuming that such engagement has been effected-the handle is moved to its Release position shown in broken lines in FIGURE 4, whereupon a lug 47 on the handle engages a shoulder on the adjacent edge of the pawl and moves the pawl out of the orbit of the ratchet teeth.

Stops 48 and 49 on the handle 44 engage the opposite edges of the adjacent leg 24 to define the limits of movement of the handle.

Inasmuch as the movement of the handle 44 from one position to the other is simply an arcuate swinging motion, this adjustment of the handle can be effected from a remote point-as, for instance, from the handlebars of a lawn mower, through a conventional Bowden wire control.

It should also be noted that the location of the handle 44 on the starter is not limited to one point. It can be located adjacent to any one of the legs 24. This flexibility makes it easier for the engine manufacturer to meet different customer requirements.

The lockout device 4-6 comprises a shallow cup-shape cover disc 50 slidably splined to the driving element 14 of the overrunning clutch, at the underside of the ratchet disc, to be movable axially between an operative position in which its rim 51 is interposed between the ratchet teeth 41 and the pawl 42, and an inoperative position uncovering the ratchet teeth and permitting engagement of the pawl therewith. The lockout device is held in its operative condition preventing engagement of the pawl with the ratchet teeth. by a coil spring 52 which encircles the driving element 1.4 of the clutch and is confined between an upwardly facing shoulder 53 on this element and the underside of the cover disc 56). To enable the spring to receive support from the shoulder 53, which actually consists of four angularly spaced segments. as best seen in FIGURE 10, the lower convolution of the spring is substantially square.

The upper end portion of the driving element 14 eX- tends into the hole 54 of the hub 37, both of which are generally square in cross section, as best seen in FIGURE 6; but the corner portions 55 of the hole are angularly wider than are the corners 56 of the driving element 14. This relationship between the cross sectional shape of the driving element 14 and the shape of the hole 54 in the hub provides a lost motion though positive torque transmitting connection between the hub and the driving element, enabling the hub 37 to have limited rotary motion with respect to the driving element 14. In practice this permitted relative rotation is on the order of 18.

In the normal condition of the starter when the clutch 12 is disengaged so that there is no restraint upon free rotation of its driving element 14, substantially all of the 18 of lost motion in the torque transmitting connection between the hub 37 and the driving element 14 is taken up in the counterclockwise, that is, the nondriving, direction, as viewed from the top in FIGURE 3. This take-up of the lost motion is effected by an impositive torque transmitting connection between the hub and the driving element formed by interengaging cam and cam follower means 57 on the lockout cover disc 46, which it will be recalled is slidably splined to the driving element 14, and the hub, or more specifically, the ratchet disc 40 thereon.

The cam and cam follower means 57 consists of four lugs 58 which project downwardly from the underside of the ratchet disc 40 through holes 59 in the lockout cover disc 50. The lugs 58 slope downwardly in the counterclockwise direction when viewed from above, and preferably the edges of the holes 59 which engage the downwardly facing sides of the lugs, have correspondingly disposed lips 60 to provide surface-to-surface engagement between the lugs and the edges of the holes, rather than mere line contact therebetween.

Because of the direction in which the lugs 53 slope, the upward thrust of the spring 52 against the underside of the cover disc 59 in bringing the same to its operative ratchet covering position, imparts clockwise rotation to the driving element 14, thereby taking up substantially all of the lost motion in the nondriving direction with respect to the hub 37.

Hence, when the starter is in its normal at rest condition, the hub 37 and the driving element 14 are substantially in their relative positions shown in FIGURE 3.

During the initial spring winding rotation of the handle 11, there is no resistance to rotation of tie driving element 14 of the clutch until its lobe 1'7 wedges one of the balls 16 against the adjacent cam surface 15-or, in other words, until the clutch 12 is engaged. Accordingly, during this interval the impositive torque transmitting connection above described causes the driving element 14 to rotate in unison with the hub; but when the clutch 12 is engaged and further rotation of the driving element 14 is resisted, the continued rotation of the hub 37 as it is dragged along by the inner end of the spring, acting through the cam and cam follower connection 57, will effect axial downward movement of the ratchet cover disc 50 against the thrust of its spring 52. All the while this is taking place, the clutch 12 is, of course, engaged-in fact, its engagement is essential to the described functioning of the cam and cam follower means.

By the time approximately 9 of the lost motion in the torque transmitting connection between the hub 37 and the driving element 14 of the clutch is taken up, the ratchet cover disc 51' will have been moved downwardly far enough to uncover the ratchet teeth, whereupon the spring loaded pawl 52 snaps into engagement with the tooth edge of the ratchet disc. If perchance the pawl seats upon the extremity of one of the teeth 41, the continued rotation of the hub which is readily accommodated by the remaining lost motion in the connection between the hub 37 and the driving element 14, will bring a tooth space into alignment with the pawl, and thereby enable the pawl to engage between the teeth. The instant this happens the hub 37 is securely held against further rotation and, consequently, as rotation of the handle 11 is continued, the spring will be wound up. As it is, the pawl and ratchet 3536 secures the handle and, hence, the outer end of the spring-against retrograde rotation.

Although only approximately 9 of relative rotation between the driving element 14 of the clutch and the hub 37 is required to impart to the ratchet cover disc 50 the downward motion needed to expose the ratchet teeth, an additional 9 of lost motion is provided despite the slight slack it introduces into the driving connection between the starter spring and the crankshaft. This additional lost motion has two purposes-4t enables the ratchet disc 49 to shift if necessary to bring a tooth space into alignment with the pawl 42 in the event the pawl happens to sit upon the top of a tooth, and it provides needed manufacturing tolerances.

When the spring has been sufi'iciently tensioned, the handle can be folded to its inoperative position and the starter left in its potentially operative condition until it is desired to actually start the engine. To do so requires merely moving the handle 44 to its Release position, shown in dotted lines in FIGURE 4. Such movement of the handle 44 withdraws the pawl 42 from engagement with the ratchet and releases the energy stored in the spring.

With the release of the energy stored in the spring, any remaining lost motion between the hub 37 and the driving element 14 of the clutch is instantly taken up to provide a positive driving connection from the spring to the driving element of the clutch, which is then rapidly rotated to impart engine starting rotation to the crankshaft of the engine, and it should be observed that at the time the engine starting torque is applied to the crankshaft, there is no lost motion between the spring and the crankshaftall elements of the torque transmitting connection therebetween being solidly engaged. It follows, therefore,

that the starter of this invention may be characterized as essentially Shock Free.

As soon as the engine starts and the driven element 13 of the clutch overruns the driving element, the clutch is disengaged and the ratchet cover disc 50 is returned to its operative position, and, in. so doing, effects relative rotation between the driving element 14- and the hub 37 to again take :up the lost motion in the torque transmitting connecting between these elements, in the counter-clockwise direction, and return the parts to their original positional relationship ready for the next starting cycle.

Although it already may have been apparent from the foregoing description, attention is nevertheless directed to the fact that several parts of the mechanism perform dual functions. These are the parts which form the cam and cam follower connection 57 between the ratchet disc 40 and the cover disc 50, and the spring 52 which main tains this connection operative. These parts: 7

(1) provide the primary elements of the impositive torque transmitting connection between the hub 37 and the driving element 14 of the overrunning clutch, and

(2) effect the withdrawal of the lockout means, specifically the rim 51 on the cover disc 5t from its operative position.

It should also be understood that the attainment of the objectives of this invention is not dependent upon the starting torque being produced by a torsion spring. Any suitable energy storing device will do thoughin all cases it would undoubtedly have to be a mechanical energy storing device. Thus, for instance, an axially stretchable coiled tension spring could be used, such as that employed in the engine starter of the pending application Serial No. 184,063. The only requirement is that the energy device be connected to a torque applying member (the hub 37) in a manner such that the released energy will be translated into torque, and that the energy storing device can be held by that torque applying memher as it is energized or tensioned.

rom the foregoing description, taken in connection with the accompanying drawings, it should be apparent to those skilled in this art that this invention provides a greatly improved spring-type starter for internal combustion engines of the type commonly used on rotary power lawn mowers.

What is claimed as my invention is:

1. In a starter for internal combustion engines having a crankshaft, of the type wherein the release of energy in an energized energy storing device imparts engine starting torque to the crankshaft of the engine, the improvement which comprises:

(A) a rotatable torque applying member connected with the energy storing device, through which (1) the released energy of the energy storing device is translated into torque, and by which (2) the energy storing device is held while being energized;

(B) a rotatable driving member connectible with the engine crankshaft to transmit torque thereto;

(C) means providing a lost motion torque transmitting connection between said members;

(D) means reacting between said members to yieldingly take up the lost motion in said connection in the direction permitting relative rotation of said members in consequence of rotation of the torque applying member in the direction it turns during the application of engine-starting torque to the crankshaft while the driving member is restra-ined from turning;

(E) manually releasable holding means to hold said torque applying member against turning and there by enable the energy storing device to be energized and to restrain said device against releasing its stored energy until desired, said holding means including (1) coacting abutrnents which must be engaged for the holding means to be operative;

(F) lockout means to prevent engagement of said abutments;

(G) biasing means acting on the lockout means to yieldingly maintain the same operative; and

(H) motion translating means operatively connected with the lookout means and operable only in consequence of said relative rotation (element D) between the torque applying and driving members to render the lockout means inoperative.

2. In an engine starter, the improvement set forth in claim 1 wherein element D comprises:

(A) cam means on one of said two rotatable members engaged with cam follower means on the other member, operable to translate relative axial motion of said members in one direction into relative rotation thereof in the direction specified in element D of claim 1, and

(B) biasing means acting upon one of said members to yieldingly hold said members in positions of axial relationship from which they move to efiect said specified relative rotation.

3. In an engine starter, the improvement set forth in claim 1, wherein element E comprises:

(A) ratchet means on the torque applying member having teeth arranged in a circle coaxial with the torque applying member, and

(B) a spring loaded pawl mounted on stationary S2112- ture of the engine and manually movable to and from an operative position automatically engageable with a tooth of said ratchet means when the lockout means is rendered inoperative.

4. In an engine starter, the improvement set forth in claim 3, wherein the lockout means comprises:

(A) a disc having a rim to encircle the teeth of the ratchet means,

(1) said disc being axially movable with respect to the ratchet means to and from an operative position at which its rim encircles the teeth and lies between them and the pawl.

5. In an engine starter, the improvement set forth in claim 4, wherein (A) said disc is slidably splined to the driving member,

and wherein (B) said motion translating means (element H of claim 1) comprises engaging cam and cam follower means on said disc and the torque applying member.

6. In a starter for internal combustion engines having a crankshaft, of the type wherein release of the energy stored in a tensioned spring and acting through an overrunning clutch which has a driven element fixed to the engine crankshaft, a driving element, and means to drivingly connect said elements and efifect engagement of the clutch after some rotation of the driving element with respect to the driven element, imparts engine-starting torque to the crankshaft of the engine, the improvement which comprises:

(A) a rotatable torque applying member coaxial with the driving element of the clutch and connected with one end of the spring to translate its released energy into torque;

(B) means providing a lost motion, through positive torque transmitting connection between the rotatable torque applying member and the driving element of the clutch, through which the torque resulting from the released spring energy is applied to the engine crankshaft after the clutch is engaged;

(C) a disc slidably splined to the driving element of the clutch for axial movement thereof between defined limits along the driving element;

(D) cam means reacting between the dies and the rotatable torque applying member to translate axial movement of the disc into relative rotation between said member and the driving element of the clutch,

(l) the slope of the cam means being such that at the limit of axial motion of the disc toward the torque applying member, the lost motion in the positive torque transmitting connection permits rotation of the torque applying member in the engine-starting direction with respect to the driving element of the clutch; and

(E) a spring reacting between the disc and the driving element of the clutch yieldingly urging the disc toward said rotatable torque applying member (1) so that the spring acting through the cam means provides an impositive torque transmitting connection between the torque applying member and the driving element of the clutch to gently effect engagement of the clutch and apply the load of the engine to the driving element of the clutch as the torque applying member turns with respect to the driving element of the clutch and the lost motion connection therebetween is taken up.

7, In an engine starter, the improvement set forth in claim 6 further characterized by:

(A) manually releasable holding means to restrain the torque apply-ting member from turning, to

(1) enable the spring to be tensioned and (2) hold the same in its tensioned condition until it is desired to release its stored energy; and

(B) lockout means on said disc (element C of claim 6) to prevent activation of the holding means as long as said disc is at its limit of axial motion to which it is urged by said spring (element E of claim 6).

8. In an engine starter, the improvement set forth in claim 7, wherein (A) said holding means comprises (1) ratchet teeth coaxial with and non-rotatably connected with the torque applying member; and

(2) a spring loaded pawl mounted on a stationary part of the engine for movement to and from an operative position engaging any one of said teeth; and wherein (B) said lockout means is a rim on said disc (element C of claim 6) which rim encircles the teeth and lies between the teeth and the pawl to thus prevent such engagement when the disc is in its operative position.

9. In a starter for internal combustion engines of the type wherein the released energy of a mechanical energy storing device acting through an overrunning clutch having a rotatable driving element imparts engine-starting torque to the crankshaft of the engine, the improvement which comprises:

(A) a rotatable torque applying member connected with the mechanical energy storing device, through which (1) the released energy of said energy storing device is translated into torque, and

(2) the mechanical energy storing device is held while being energized;

(B) means providing a positive though lost motion torque transmitting connection between said torque applying member and the driving element of the clutch;

(C) means providing an impositive torque transmitting connection between said torque applying member and the driving element of the clutch including (1) cooperating parts one of which is connected with said torque applying member and the other of which is connected with the driving element of the clutch; and

(2) means yieldingly holding said cooperating parts in predetermined positional relationship in which they turn in unison and impart rotation to the driving element of the clutch as long as the clutch remains disengaged so that the load of the engine does not resist rotation of said driving element, While allowing said cooperating parts to turn with respect to one another after the clutch is engaged and until the lost motion in said posi tive torque transmitting connection is taken up;

(D) manually releasable pawl and ratchet means to hold said torque applying member against turning and thereby enable the mechanical energy storing device to be energized and to restrain said device from releasing its stored energy until desired;

(E) lockout means to prevent engagement of the pawl and ratchet;

(F) biasing means acting on the lockout means to normally render the same operative; and

(G) means operatively connected with the lockout means and operative in consequence of said relative rotation between said two cooperating parts of the impositive torque transmitting connection as the lost motion in the positive torque transmitting connection is taken up, to render said lockout means ineffective and thus permit engagement of the pawl and ratchet means.

10. In a windup spring-type starter for internal combustion engines, wherein the released energy of a wound up spirally coiled spring acting through an overrunning unidirectional clutch having a rotatable driving element imparts engine-starting torque to the crankshaft of the engine, the improvement which comprises:

(A) means connected to one end of the spring to wind up and tension the same while the other end thereof is held, said means including (1) a handle mounted to turn about the axis of the clutch;

(B) means providing a lost motion torque transmitting connection between the other end of the spring and said driving element of the clutch;

(C) a ratchet member in fixed torque transmitting relation with said other end of the spring, said ratchet member having 1) teeth disposed concentrically with respect to the driving element of the clutch;

(D) a pawl;

(E) means mounting the pawl upon stationary structure of the engine for movement into and out of 10 engagement with a tooth of the ratchet member, to thereby hold the ratchet member and said other end of the spring against turning as the spring is wound (F) normally operative lockout means to prevent engagement of the pawl with a tooth of the ratchet member; and

(G) means operative in consequence of relative rotation between said other end of the spring and the driving element of the clutch as the clutch engages and the load of the engine is picked up, to render said lockout means ineflective and thus permit engagement of the pawl with a tooth on the ratchet member.

11. A wind-up spring-type starter for an internal combustion engine having a crankshaft, comprising:

(A) an overrunning unidirectional clutch having (1) a driven element fixed to the crankshaft of the engine, (2) a driving element, and (3) means to releasably connect said elements for the transmission of engine-starting torque from the driving to the driven element;

(B) a spirally coiled spring;

(C) means connected with one end of the spring to wind and tension the same, said means including (1) a handle mounted to turn about the axis of the clutch;

(D) a rotatable torque transmitting member coaxial with the driving element of the clutch, connected in torque transmitting relation with the other end of the spring;

(E) means providing a lost motion torque transmitting connection between said rotatable torque transmitting member and the driving element of the clutch;

(F) ratchet teeth concentric to and in fixed torque transmitting relation with said rotatable torque transmitting member;

(G) a pawl;

(H) means mounting the pawl upon stationary structure of the engine for movement into and out of engagement with a tooth of said ratchet member to thereby hold said rotatable torque transmitting member and the end of the spring connected therewith against turning as the spring is wound up;

(I) a barrier movable to and from an operative position interposed between the pawl and the ratchet member to prevent engagement of the pawl with a tooth of the ratchet member; and

(J) cam means acting upon said barrier and operative in consequence of relative rotation between said rotatable torque transmitting member and the driving element of the clutch to move the barrier out of its operative position and thereby enable engagement of the pawl with a tooth on the ratchet member.

12. In a starter for internal combustion engines having a crankshaft, of the type wherein the release of energy in an energized mechanical energy storing device imparts engine-starting torque to the crankshaft of the engine, through an overrunning clutch, the improvement which comprises:

(A) a rotatable torque applying member connected with the mechanical energy storing device, through which (1) the released energy of the mechanical energy storing device is translated into torque, and by which (2) the mechanical energy storing device is held while being energized;

(B) a rotatable driving member connectible with the engine crankshaft through the overrunning clutch; (C) means providing a lost motion though positive torque transmitting connection between said members;

(D) manually releasable holding means to hold said torque applying member against turning and thereby enable the mechanical energy storing device to be energized and to restrain said device against releasing its stored energy until desired, said holding means including (1) coacting abutments which must be engaged for the holding means to be operative; (E) lockout vmeans .to prevent engagement of said abutments;

.(F) biasing means acting on said lockout means to yieldingly maintain the same operative; and (G) common means operatively connected with the torque applying member and the driving member and including as an element thereof said biasing means, to

(1) provide an impositive torque transmitting connection between said members by yieldingly taking up the lost motion in said torque transmitting connection between said members in the direction yieldingly permitting relative rotation thereof in consequence of rotation of the torque applying member in the direction it turns during the application of engine-starting torque to the crankshaft while-the driving member is restained from turning, and to (2) render the lockout means inoperative in con- 7 sequence of the relative rotation between said members.

13. In an engine starter, the improvement set forth in claim 12, wherein said common means (element G of claim 12) comprises:

(A) a disc member slidably splined to the driving memher and carrying the lockout means,

(1) the biasing means reacting between said disc member and the driving member; and (B) cam and cam follower means on the torque applying member and the disc member,

(1) maintained in engagement by the biasing means, and

(2) coacting to translate said relative rotation between the torque applying and driving members which takes place after engagement of the clutch, into axial motion of the disc member in the direction to withdraw the lockout means from its operative position, and

(3) to translate the opposite axial motion of the disc member which is produced by the biasing means when the engine starts and the overrunning clutch disengages, into relative rotation between the torque applying and driving members to take up the lost motion in the positive torque transmitting connection therebetween, in the direction opposite that specified in element G (1) of claim 12.

No References Cited. 

1. IN A STARTER FOR INTERNAL COMBUSTION ENGINES HAVING A CRANKSHAFT, OF THE TYPER WHEREIN THE RELEASE OF ENERGY IN AN ENERGIZED ENERGY STORING DEVICE IMPARTS ENGINE STARTING TORQUE TO THE CRANKSHAFT OF THE ENGINE, THE IMPROVEMENT WHICH COMPRISES: (A) A ROTATABLE TORQUE APPLYING MEMBER CONNECTED WITH THE ENERGY STORING DEVICE, THROUGH WHICH (1) THE RELEASED ENERGY OF THE ENERGY STORING DEVICE IS TRANSLATED INTO TORQUE, AND BY WHICH (2) THE ENERGY STORING DEVICE IS HELD WHILE BEING ENERGIZED; (B) A ROTATABLE DRIVING MEMBER CONNECTIBLE WITH THE ENGING CRANKSHAFT TO TRANSMIT TORQUE THERETO; (C) MEANS PROVIDING A LOST MOTION TORQUE TRANSMITTING CONNECTION BETWEEN SAID MEMBERS; (D) MEANS REACTING BETWEEN SAID MEMBERS TO YIELDINGLY TAKE UP THE LOST MOTION IN SAID CONNECTION IN THE DIRECTION PERMITTING RELATIVE ROTATION OF SAID MEMBERS IN CONSEQUENCE OF ROTATION OF THE TORQUE APPLYING MEMBER IN THE DIRECTION IT TURNS DURING THE APPLICATION OF ENGINE-STARTING TORQUE TO THE CRANKSHAFT WHILE THE DRIVING MEMBER IS RESTRAINED FROM TURNING; (E) MANUALLY RELEASABLE HOLDING MEANS TO HOLD SAID TORQUE APPLYING MEMBER AGAINST TURNING AND THEREBY ENABLE THE ENERGY STORING DEVICE TO BE ENERGIZED 